Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Science 10 January 1969:
Vol. 163. no. 3863, pp. 177 - 179
DOI: 10.1126/science.163.3863.177
Prev | Table of Contents | Next

Articles

Seismic Waves Reflected from Discontinuities within Earth's Upper Mantle

Eric R. Engdahl 1 and Edward A. Flinn 2

1 Environmental Science Services Administration, Coast and Geodetic Survey, Rockville, Maryland 20852
2 Geotech (a Teledyne Company), Alexandria, Virginia 22313

Precursors to normtial seismic waves of the PKPPKP type in the distance range of 55° to 75° are ascribed to reflection of this phase from within the earth's upper mantle. The new observations confirm the existence of a sharply defined transition zone, probably worldwide in extent, at a depth of approximately 650 kilometers. These data are shown to be a useful tool for the study of upper mantle structure on a global basis.


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
P`P` Precursors Under Africa: Evidence for Mid-Mantle Reflectors.
Y. LeStunff, C. W. Wicks Jr., and B. Romanowicz (1995)
Science 270, 74-77
   Abstract »    PDF »
Structure of the mantle beneath Montana LASA from analysis of long-period, mode-converted phases.
D. R. BAUMGARDT and S. S. ALEXANDER (1984)
Bulletin of the Seismological Society of America 74, 1683-1702
   Abstract »    PDF »
The Earth as a Planet: Paradigms and Paradoxes.
D. L. Anderson and D. L. Anderson (1984)
Science 223, 347-355
   Abstract »    PDF »
Application of arrays in the detection, location, and identification of seismic events.
F. RINGDAL and E. S. HUSEBYE (1982)
Bulletin of the Seismological Society of America 72, S201-S224
   Abstract »    PDF »
A note on the interpretation of precursors to PKPPKP.
D. W. KING and J. R. CLEARY (1974)
Bulletin of the Seismological Society of America 64, 721-723
   PDF »
Upper-mantle discontinuity from amplitude data of P'P' and its precursors.
T.-L. TENG and J. P. TUNG (1973)
Bulletin of the Seismological Society of America 63, 587-597
   Abstract »    PDF »
Asymmetric P'P': An alternative to P'dP' reflections in the uppermost mantle (0 to 110 km).
J. H. WHITCOMB (1973)
Bulletin of the Seismological Society of America 63, 133-143
   Abstract »    PDF »
Array studies of seismic waves arriving between P and PP in the distance range 90{degrees} to 115{degrees}.
C. WRIGHT (1972)
Bulletin of the Seismological Society of America 62, 385-400
   Abstract »    PDF »
Reflections from discontinuities beneath antarctica.
R. D. ADAMS (1971)
Bulletin of the Seismological Society of America 61, 1441-1451
   Abstract »    PDF »
Remarks on the paper "Early reflections of P'P' as an indication of upper mantle structure," by R. D. Adams.
E. R. ENGDAHL and E. A. FLINN (1969)
Bulletin of the Seismological Society of America 59, 1415-1417
   PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)